Gas permeable electrode and method of manufacture

Abstract

A gas permeable or breathable electrode and method of manufacture thereof. In one example there is an electrolytic cell having an electrode comprising a porous material, wherein gas produced at the electrode diffuses out of the cell via the porous material. In operation the gas is produced at the at least one electrode without substantial bubble formation. In another example there is an electrode having a porous conducting material with a hydrophobic layer or coating applied to a side of the porous conducting material. A catalyst may be applied to another side. The gas permeable or breathable electrode can be used in an electrolytic cell, electrochemical cell, battery and/or fuel cell. Gas produced at the electrode diffuses out of a cell via at least part of the electrode, separating the gas from the reaction at the electrode.

The invention claimed is: 
     
       1. An electrolytic cell comprising a first electrode and a second electrode, wherein at least one of the first and second electrodes comprises a porous material, wherein gas produced at the at least one electrode diffuses out of the cell via the porous material, and wherein a spacing between the first and second electrodes is permeable to gases. 
     
     
       2. The electrolytic cell according to  claim 1 , wherein in operation the gas is produced at the at least one electrode without bubble formation or without substantial bubble formation. 
     
     
       3. The electrolytic cell according to  claim 1 , wherein greater than 90% of the gas produced at the at least one electrode is removed from the cell across or through the porous material. 
     
     
       4. The electrolytic cell according to  claim 1 , wherein greater than 95% of the gas produced at the at least one electrode is removed from the cell across or through the porous material. 
     
     
       5. The electrolytic cell according to  claim 1 , wherein greater than 99% of the gas produced at the at least one electrode is removed from the cell across or through the porous material. 
     
     
       6. The electrolytic cell according to  claim 1 , wherein the porous material is electrolyte impermeable. 
     
     
       7. The electrolytic cell according to  claim 1 , wherein the gas produced forms bubbles less than 125 μm in average diameter. 
     
     
       8. The electrolytic cell according to  claim 1 , wherein the gas produced forms bubbles less than 100 μm in average diameter. 
     
     
       9. The electrolytic cell according to  claim 1 , wherein the gas produced forms bubbles less than 50 μm in average diameter. 
     
     
       10. The electrolytic cell according to  claim 1 , wherein the at least one electrode is a cathode, and wherein in operation the gas produced at the cathode diffuses out of the cell via the porous material, separating the gas from a cathodic reaction without substantial bubble formation. 
     
     
       11. The electrolytic cell according to  claim 1 , wherein the at least one electrode is an anode, and wherein in operation the gas produced at the anode diffuses out of the cell via the porous material, separating the gas from an anodic reaction without substantial bubble formation. 
     
     
       12. The electrolytic cell according to  claim 1 , wherein the porous material is at least partly hydrophobic. 
     
     
       13. The electrolytic cell according to  claim 1 , wherein the porous material includes or has a thin-film coating applied. 
     
     
       14. The electrolytic cell according to  claim 13 , wherein the thin-film coating is hydrophobic. 
     
     
       15. The electrolytic cell according to  claim 13 , wherein the thin-film coating is selected from the group comprising silicone-fluoropolymer, polydimethylsiloxane (PDMS) or its copolymers with fluoromonomers, PDD-TFE (perfluoro-2, 2-dimethyl-1, 3-dioxole with tetrafluoroethylene), polyvinyl fluoride, polyvinyl chloride, nylon 8,8, nylon 9,9, polystyrene, polyvinylidene fluoride, poly n-butyl methacrylates, polytrifluoroethylene, nylon 10,10, polybutadiene, polyethylene polychlorotrifluoroethylene, polypropylene, polydimethylsiloxane, poly t-butyl methacrylates, fluorinated ethylene propylene, hexatriacontane, paraffin, polytetrafluoroethylene, poly(hexafluoropropylene), polyisobutylene or combinations thereof. 
     
     
       16. The electrolytic cell according to  claim 12 , wherein the porous material has an average pore size of less than 0.5 μm. 
     
     
       17. The electrolytic cell according to  claim 12 , wherein the porous material has an average pore size of less than 0.1 μm. 
     
     
       18. The electrolytic cell according to  claim 12 , wherein the porous material has an average pore size of less than 0.05 μm. 
     
     
       19. The electrolytic cell according to  claim 1 , which further includes a catalyst associated with the porous material. 
     
     
       20. The electrolytic cell according to  claim 19 , wherein the catalyst is selected from the group comprising Pt, Au, Pd, Ru, Ir, Mn, Fe, Ni, Co, NiO x , Mn complexes, Fe complexes, MoS x , CdS, CdSe, and GaAs or combinations thereof. 
     
     
       21. The electrolytic cell according to  claim 1 , for use in gas synthesis. 
     
     
       22. The electrolytic cell according to  claim 1 , for use in a battery. 
     
     
       23. The electrolytic cell according to  claim 1 , for use in a fuel cell. 
     
     
       24. The electrolytic cell according to  claim 1 , for use in the production of nitrous oxide. 
     
     
       25. The electrolytic cell according to  claim 1 , for use in the production of ammonia. 
     
     
       26. An electrolytic cell, comprising:
 a cathode comprising a first porous material; 
 an anode comprising a second porous material; and, 
 at least one electrolyte for at least partial immersion of the cathode and the anode; 
 wherein in operation gases are produced at the cathode and the anode without substantial bubble formation and the gases diffuse out of the cell via the porous materials; and 
 wherein a spacing between the cathode and the anode is permeable to gases. 
 
     
     
       27. A method of producing gas using an electrolytic cell, the method comprising the steps of:
 providing a cathode comprising a first porous material; 
 providing an anode comprising a second porous material; 
 at least partially immersing the cathode and the anode in at least one electrolyte; and 
 passing a current through the anode and the cathode; 
 wherein gas produced at the anode diffuses out of the cell via the second porous material, and wherein gas produced at the cathode diffuses out of the cell via the first porous material; and 
 wherein a spacing between the cathode and the anode is permeable to gases. 
 
     
     
       28. A method of producing gas using an electrolytic cell, the method comprising:
 producing gas at an electrode; 
 diffusing the gas out of the cell via an electrolyte-impermeable porous material of the electrode; and 
 separating the gas produced without substantial bubble formation at the electrode. 
 
     
     
       29. The method according to  claim 28 , wherein more than 90% of the gas is separated at the electrode by transporting the gas across the porous material adjacent or near a catalytic surface. 
     
     
       30. The method according to  claim 28 , wherein the gas is separated without formation of bubbles larger than 125 μm in average diameter. 
     
     
       31. An electrolytic cell having at least one electrode comprising an electrolyte-impermeable porous material, wherein gas produced at the at least one electrode diffuses out of the cell via the porous material, and wherein the electrolytic cell does not comprise a separator.